The subject matter of the present invention is catalyst systems containing imidochromium compounds, new imidochromium complexes, a process for the polymerization of olefins as well as a process for the production of imidochromium complexes.
Many of the catalysts employed for the polymerization of xcex1-olefins are based on immobilized chromium oxides (see, for example, Kirk-Othmer, xe2x80x9cEncyclopedia of Chemical Technologyxe2x80x9d, 1981, Volume 16, page 402). Such catalysts generally yield ethylene homopolymers and ethylene copolymers having high molecular weights although they are relatively insensitive to hydrogen, as a result of which they do not allow a simple control of the molecular weight. In contrast, the use of bis(cyclopentadienyl)chromium (U.S. Pat. No. 3,709,853), bis(indenyl)chromium or bis(fluorenyl)chromium (U.S. Pat. No. 4,015,059), which is applied onto an inorganic, oxidic support, makes it possible to easily regulate the molecular weight of polyethylene through the addition of hydrogen.
As is the case with Ziegler-Natta systems, chemists have recently sought for catalyst systems having a uniformly defined, active center, the so-called single-site catalysts, also for chromium compounds. The systematic variation of the ligand skeleton is supposed to make it easy to change the activity, the copolymerization behavior of the catalyst and the properties of the polymers thus obtained.
The preparation of bis(tert.-butylimido)bis(trimethylsiloxy)chromium by means of the reaction of dioxochromium dichloride with tert.-butyl(trimethylsilyl)amine was described by W. Nugent et al. in Inorg. Chem. 1980, 19, pages 777 to 779. Diaryl derivatives of this compound, namely, bis(tert.-butylimido)di(aryl)chromium were prepared by G. Wilkinson et al. as presented in J. Chem. Soc. Dalt. Trans. 1988, pages 53 to 60. The corresponding dialkyl complexes were described for the first time by C. Schaverien et al. (Organomet. 9 (1990), pages 774 to 782). They were also able to isolate a monoimidochromium compound tert.-butylimido(oxo)chromium dichloride by reacting tert.-butyl-imido-bis(trimethylsilanolato)oxochromium with phosphorus pentachloride (W. Nugent in Inorg. Chem. 1983, 22, pages 965 to 969).
EP-A 0,641,804 describes the use of bis(alkylimido)chromium(VI) and bis(arylimido)chromium(VI) complexes for the polymerization of olefins. In EP-A 0,816,384, these bis(imido)chromium(VI) complexes are supported on polyaminostyrene for the polymerization of ethylene and copolymerization of ethylene with higher xcex1-olefins. In this context, the preparation of bis(arylimido)chromium dichloride is a three-stage synthesis route since the reaction of dioxochromium dichloride with N-trimethyl-silylanilines does not yield bis(arylimido)chromium dichloride.
G. Wilkinson et al., were able to prepare tert.-butylimidochromium(V)trichloride and its donor-coordinated derivatives (J. Chem. Soc. Dalt. Trans. 1991, pages 2051 to 2061).
The objective of the present invention was to find new catalyst systems that can be easily modified and that are suitable for the polymerization of xcex1-olefins.
Moreover, the objective was to find an improved synthesis route for the preparation of bis(imido)chromium(VI) compounds.
Accordingly, catalyst systems have been found, containing
(A) at least one imidochromium compound, which can be obtained by a process encompassing the following process steps:
(a) contacting a dioxochromium compound with an N-sulfinyl compound R1xe2x80x94Nxe2x95x90Sxe2x95x90O or R2xe2x80x94Nxe2x95x90Sxe2x95x90O, wherein the variables have the following meaning:
R1 stands for C1-C20-alkyl, C2-C20-alkanyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, whereby the organic radical R1 can also have inert substituents, for SiR33;
R2 stands for R3Cxe2x95x90NR4, R2Cxe2x95x90O, R3Cxe2x95x90O(OR4), R3Cxe2x95x90S, (R3)2Pxe2x95x90O, (OR3)2Pxe2x95x90O, SO2R3, R5R4Cxe2x95x90N, NR5R4 or BR5R4;
R3, R4 independent of each other, stand for C1-C20-alkyl, C2-C30-alkenyl, C4-C30-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R3 and R4 can also have inert substituents;
(b) contacting the reaction product thus obtained with chlorine if a sulfinyl compound R1xe2x80x94Nxe2x95x90Sxe2x95x90O was used and, in case an N-sulfinyl compound R2xe2x80x94Nxe2x95x90Sxe2x95x90O was used, with chloride or sulfurylchloride or with no other reagent;
(B) at least one activator compound
and
(C) optionally, one or more additional catalysts commonly employed for the polymerization of olefins.
Furthermore, imidochromium compounds having the general formula II, 
were found, wherein the variables have the following meaning:
R2 stands for R3Cxe2x95x90NR4, R3Cxe2x95x90O, R3Cxe2x95x90O(OR4), R3Cxe2x95x90S, (R3)2Pxe2x95x90O, (OR3)2Pxe2x95x90O, SO2R2, R3R4Cxe2x95x90N, NR3R4 or BR3R4;
X independent of each other, strands for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)3, OR5, OSi(R5)2, SO3R5, OC(O)R5, xcex2-diketonate, sulfate, dicarboxylates, dialcoholates, BF4xe2x88x92, PF6xe2x88x92, or bulky weakly on non-coordinating anions;
R3-R6 independent of each other, stand for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl, having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R3 and R4 can also have insert substituents;
m is 1 for dianionic X, 2 for monoanionic X.
Imidochromium compounds having the general formula III, 
were likewise found, wherein the variables have the following meaning:
R2 stands for R3Cxe2x95x90NR4, R3Cxe2x95x90O, R3Cxe2x95x90O(OR4), R3Cxe2x95x90S, (R3)2Pxe2x95x90O, (OR3)2Pxe2x95x90O, SO2R3, R3R4Cxe2x95x90N, NR3R4 or BR3R4;
X independent of each other, stands for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)3, OR5, OSi(R5)3, SO3R5, OC(O)R5, xcex2-diketonate, sulfate, dicarboxylates, dialcoholates, BF4xe2x88x92, PF6xe2x88x92, or bulky weakly or non-coordinating anions;
R5-R6 independent of each other, stand for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R3 to R6 can also have insert substituents;
m is 1 for dianionic X, 2 for monoanionic X;
L is a neutral donor;
n is 0 to 3;
Furthermore, a process was found for the production of an imidochromium compound having the general formula IV, 
wherein the variables have the following meaning:
R1 stands for C1-C20-alkyl, C2-C20-alkenyl, C0-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, whereby the organic radical R1 can also have inert substituents, or SiR33;
Z independent of each other, stands for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)3, OR5, OSi(R5)3, SO3R5, OC(O)R5, xcex2-diketonate, sulfate, dicarboxylates, dialcoholates, BF4xe2x88x92, PF6xe2x88x92, or bulky weakly or non-coordinating anions;
R3, R5, R6 independent of each other, stand for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R3, R5 and R6 can also have inert substituents;
p is 1 for dianionic Z, 2 for monoanionic Z;
characterized in that a dioxochromium compound is reacted with an N-sulfinyl compound R1xe2x80x94NSO.
A process for the production of an imidochromium compound having the general formula I, 
was likewise found, wherein
X independent of each other, stands for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)3, OR5, OSi(R5)3, SO3R5, OC(O)R5, xcex2-diketonate, sulfate, dicarboxylates, dialcoholates, BF4xe2x88x92, PF6xe2x88x92, or bulk weakly or non-coordinating anions;
R1 stands for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, whereby the organic radical R1 can also have inert substituents, or SiR33;
R3,R5, R6 independent of each other, stand for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R3, R5 and R6 can also have inert substituents;
L is a neutral donor;
n is 0 to 3;
m is 1 for dianionic X, 2 for monoanionic X;
characterized in that an imidochromium compound having the general formula V 
wherein the variables have the following meaning:
R1 stands for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, whereby the organic radical R1 can also have inert substituents, or SiR33;
X independent of each other, stands for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)2, OR5, OSi(R5)3, SO3R5, OC(O)R3, xcex2-diketonate, sulfate, dicarboxylates, dialcoholates, BR4xe2x88x92, PF6xe2x88x92, or bulky wekly or non-coordinating anions;
R5, R5, R6 independent of each other, stand for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R3, R5 and R6 can also have inert substituents;
m is 1 for dianionic X, 2 for monoanionic X;
is reacted with chlorine.
A process for the production of an imidochromium compound having the general formula III, 
was likewise found, wherein the variables have the following meaning:
R2 stands for R3Cxe2x95x90NR4, R2Cxe2x95x90O, R3Cxe2x95x90O(OR4), R3Cxe2x95x90S (R3)2Pxe2x95x90O, (OR3)2Pxe2x95x90O, SO2R3, R5R4Cxe2x95x90N, NR3R4 or BR3R4;
X independent of each other, stands for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)3, OR5, OSi(R5)3, SO3R5, xcex2-diketonate, sulfate, dicarboxylates, dialcoholates, BF4xe2x88x92, PF6xe2x88x92, or bulky weakly or non-coordinating anions;
R5-R6 independent of each other, stand for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atom in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R2 to R6 can also have inert substituents;
L is a neutral donor;
n is 0 to 3;
m is 1 for dianionic X, 2 for monoanionic X;
characterized in that a dioxochromium compound is reacted with an N-sulfinyl compound R2xe2x80x94Nxe2x95x90Sxe2x95x90O in the presence of chlorine or sulfurylchloride.
A process for the production of an imidochromium compound having the general formula VI, 
was likewise found, wherein the variables have the following meaning:
R2 stands for R3Cxe2x95x90NR4, R3Cxe2x95x90O, R3Cxe2x95x90O(OR4), R3Cxe2x95x90S, (R3)2Pxe2x95x90O, (OR3)2Pxe2x95x90O, SO2R5, R2R4Cxe2x95x90N, NR5R4 or BR3R4;
Z independent of each other, stands for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)3, OR5, OSi(R5)5, SO3R5, OC(O)R5, xcex2-diketonate, sulfate, dicarboxylates, dialcoholates, BF4xe2x88x92, PF6xe2x88x92, or bulky weakly or non-coordinating anions;
R3-R6 independent of each other, stand for C1-C20-alkyl, C3-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the lamer is bonded to a carbon atom, whereby the organic radicals R3 to R6 can also have inert substituents;
p is 1 for dianionic Z, 2 for monoanionic Z;
characterized in that a dioxochromium compound is reacted with an N-sulfinyl compound R2xe2x80x94NSO.
Furthermore, a process was found for the polymerization of olefins at temperatures within the range from 0xc2x0 C. to 300xc2x0 C. [32xc2x0 F. to 572xc2x0 F.] and at pressures ranging from 1 bar to 4000 bar, characterized in that the polymerization is carried out in the presence of a catalyst system according to the invention.
The process for the production of the chromium complexes can make use of a wide array of dioxochromium compounds as the starting materials. The important aspect is the presence of the two oxo groups. Other ligands in the chromium starting compound are, among others, the monoanionic and dianionic ligands cited for X and Z. Examples of monoanionic ligands are halogens such as, for instance, fluorine, chlorine, bromine and iodine, amides such as, for instance, dimethylamide, diethylamide and pyrrolidine, alcoholates such as, for example, methanoiate, ethanolate, isopropanolate, butanolate, phenolate and biphenolate, carboxylates such as, for instance, acetate and trifluoracetate, xcex2-diketonates such as, for example, acetylacetonate, dibenzoylmethanate, 1,1,1-trifluoropentane dionate and 1,1,1,5,5,5,-hexafluoropentane dionate, sulfonates such as for instance, toluene sulfonate and trifluoromethane sulfonate, C1-C20-alkyl, especially C1-C20-alkylsilyls such as, for example, methylene trimethylsilyl, bis-trimethylsilylmethyl, C6-C20-aryl such as, for instance, mesityl or weakly or non-coordinating anions. Examples of dianionic ligands are sulfate and chelating dicarboxylates such as, for example, oxalate, fumarate, malonate or succinate and dialcoholates such as, for instance, glycolate. One or more monoanionic or dianionic ligands can be bonded to the dioxochromium compound (also see Compr. Coord. Chem. Vol. 3, G. Wilkinson, Pergamon Press 1987, First Edition, Chapter 35.6.1.3., page 935 and Chapter 35.7.1. through 35.7.2., pages 938 to 941). In addition, one or more neutral donors L can be coordinated on the chromium educts. As a rule, the donor molecules have a heteroatom of the 15th or 16th group of the periodic table of elements. Preference is given to amines, for example, trimethylamine, dimethylamine, N,N-dimethylaniline or pyridine, ethers such as, for instance, tetrahydrofuran, diethylether, dibutylether, dimethoxyethane or dimethyldiethylene glycol, thioethers such as, for example, dimethylsulfide, esters such as, for instance, acetic and methylester, acetic acid ethylester or formic acid ethylester, ketones such as, for instance, acetone, benzophenone or acrolein. Schiff bases, xcex1-diimines, phosphines such as, for example, trimethylphosphine, triethylphosphine or triphenylphosphine, phosphites such as, for instance, trimethylphosphite or triethylphosphite, phosphine oxides, phosphoric acid esters or phosphoric acid amides such as, for example, hexamethylphosphoric acid triamide or N-oxides. The chromium compounds used can be present in a wide array of oxidation stages, preferably from +4 to +6 and especially preferred in the oxidation stage +6. Preferred dioxochromium compounds are dioxochromium dihalides while dioxochromium dichloride is especially preferred.
The N-sulfinyl compounds employed are, for example, N-sulfinylamines for R1xe2x80x94Nxe2x95x90Sxe2x95x90O, while for R3xe2x80x94Nxe2x95x90Sxe2x95x90O, they are, for example. N-sulfinylcarbamidines, N-sulfinylcarbamides, N-sulfinylcarbamates, N-sulfinylcarboxylamides, N-sulfinylthiocarboxylamides, N-sulfinylphosphonamides or N-sulfinylsulfonamides. The N-sulfinyl compounds can usually be prepared without problems and, as a rule, in a high yield, from compounds containing NH2 groups and sulfinylation agents such as thionylchloride, sulfur dioxide or else by means of other N-sulfinyl compounds (Z. Chem. [Journal of Chemistry] 22, (1982), pages 235 to 245).
The radicals R5 and R4 are C1-C20-alkyl, whereby the alkyl can be linear or branched, such as for example, methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, five-membered to seven-membered cycloalkyl which, in turn, can have a C6-C10-aryl group as the substitutent, such as, for instance, cyclopropane, cycloutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane or cyclododecane, C2-C10-alkenyl, whereby the alkenyl can be linear, cyclio or branched and the double bond can be internal or terminal, such as, for instance, vinyl, 1-allyl, 2-allyl, 3-allyl, butenyl, pentenyl, hexenyl, cyclo-pentenyl, cyclohexenyl, cyclooctanyl or cyclooctadienyl, C6-C20-aryl, whereby the aryl radical can be substituted by other alkyl groups such as, for example, phenyl, naphthyl, bi-phenyl, anthranyl, o-methylphenyl, m-methylphenyl, p-methylphenyl, 2,3-dimethylphenyl, 2,4-dimethylphenyl, 2,5-dimethylphenyl or 2,6-dimethylphenyl, 2,3,4-trimethylphenyl, 2,3,5-trimethylphenyl, 2,3,6-trimethylphenyl, 2,4,5-trimethylphenyl, 2,4,6-trimethylphenyl or 3,4,5-trimethylphenyl, or arylalkyl, whereby the arylalkyl can be substituted by other alkyl groups such as, for instance, benzyl, o-methylbenzyl, m-methylbenzyl, p-methylbenzyl, 1-ethylphenyl or 2-ethylphenyl whereby, optionally, two radicals R3 to R4 can also be joined to a five-membered or six-membered ring and/or can also have inert substituents such as halogens, for example, fluorine, chlorine or bromine. Preferred R3 and R4 radicals are hydrogen (if it is bonded to a carbon atom), methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, tert.-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, ortho-substituted or para-substituted alkyl or chloro-substituted, or bromo-substituted phenyls, ortho, ortho or ortho, paradiakyl-substituted or dichloro-substituted, or dibromo-substituted phenyls, trialkyl-substituted or trichloro-substituted phenyls, fluoro-substituted phenyls, naphthyl, biphenyl and anthranyl. Especially preferred R3 and R4 radicals are methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, allyl, benzyl, phenyl, 2-chlorophenyl, 2-methylphenyl, 2,6-dimethylphenyl, 2,4-dimethylphenyl, 2,6-diisopropylphenyl, 2,6-dichlorophenyl, 2,4-dichlorophenyl, 2,6-dibromophenyl, 2,4-dibromophenyl, 2,4,6-trimethylphenyl, 2,4,6-trichlorophenyl and pentafluorophenyl.
The R1 radical can be either a C-organic radical, as described above for R3 and R4, or also an Si-organic radical. In the case of the Si-organic substituents SiR33, there can also optionally be two R3 joined to a five-membered or six-membered ring and the three R3 radicals can be selected independent of each other such as, for example, trimethylsilyl, triethylsilyl, butyldimethylsilyl, tributylisilyl, triallylallyl, triphenylsilyl or dimethylphenylallyl. Examples of Si-organic substituents are especially trialkylsilyl groups having 1 to 10 carbon atoms in the alkyl radical, particularly triamethylallyl groups. The preferred R1 radical is methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, tert.-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, vinyl, allyl, benzyl, phenyl, ortho-substituted or para-substituted alkyl or chloro-substituted, or bromo-substituted phenyls, ortho, ortho or ortho, paradialkyl-substituted or dichloro-substituted, or dibromo-substituted phenyls, trialkyl-substituted or trichloro-substituted phenyls, fluoro-substituted phenyls, naphthyl, biphenyl and anthranyl. Especially preferred R1 radicals are benzyl, phenyl, 2-chlorophenyl, 2-methylphenyl, 2,6-dimethylphenyl, 2,4-dimethylphenyl, 2,6-diisopropylphenyl, 2,6-dichlorophenyl, 2,4-dichlorophenyl, 2,6-dibromophenyl, 2,4-dibromophenyl, 2,4,6-trimethylphenyl, 2,4,6-trichlorophenyl, pentafluorophenyl, naphthyl and anthranyl.
R2 can be an imino, isocyanide, formyl, oxo, thioxo, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, phosphinoyl, dialkoxyphosphoryl or diaryloxyphosphoryl, sulfonyl, dialkylamino or diarylamino or dialkylboryl or diaryloryl group. Preferred groups are sulfonyl and oxo, especially arylsulfonyls such as, for instance, toluene sulfonyl, benzene sulfonyl, p-trifluoromethylbenzene sulfonyl or 2,6-diisopropylbenzene sulfonyl and aryloxo such as, for example, benzoyl, 2-methylbenzoyl, 2,6-dimethylbenzoyl, 2,6-diisopropylbenzoyl and 2,4,6-trimethylbenzoyl.
Imidochromium compounds as referred to below are monoimidochromium compounds as well as bis-imidochromium compounds.
The reaction to prepare the imidochromium compound (A) is usually carried out in an inert atmosphere, for example, with nitrogen or argon as the inert gas. Reaction step (a) can be conducted at temperatures between 0xc2x0 C. and 150xc2x0 C. [32xc2x0 F. and 302xc2x0 F.], preferably between 10xc2x0 C. and 100xc2x0 C. [50xc2x0 F. and 212xc2x0 F.]. The main solvents used are aprotic solvents such as ethers, for instance, tetrahydrofuran, diethylether, dibutylether, 1,2-dimethoxyethane or diethylene glycol dimethylether, alkanes such as, for example, pentane, n-hexane, iso-hexane, n-heptane, o-octane, cyclohexane or Decalin, aromatic compounds such as, for instance, benzene, toluene or xylene, or chlorohydrocarbons such as methylene chloride, chloroform, tetrachloromethane or dichloroethane. It is also possible to employ solvent mixtures. Preference is given to alkanes and/or chlorohydrocarbons while n-octane and/or tetrachloromethane are especially preferred.
In this context, the reaction product from step (a) can be subjected to the second reaction step either with or without intermediate purification or isolation. The two reaction steps can also be performed simultaneously in one stage. Preferably, the imidochromium complex with R1 is isolated from reaction step (a) before step (b). For imidochromium complexes with R2, step (b) is optional. Therefore, the R2 imidochromium complex can also be mixed with the activator directly, without being contacted with chlorine or sulfuryl-chloride, and then employed in the polymerization. The reaction products from (a) with R2, however, can also be contacted with chlorine or sulfurylchloride and only then be mixed with the activator compound. For R2, steps (a) and (b) are preferably carried out simultaneously as a cone-pot reaction.
The ratio of the dioxochromium compound to the N-sulfinyl compound lies between 1:1 and 1:10, preferably between 1;1 and 1:3 and especially preferred between 1;1 and 1:2.5.
Reaction step (b) can be carried out analogously to the instructions given by G. Wilkinson et al. in J. Chem. Soc. Dalt. Trans. 1991, pages 2051 to 2061 using the reaction product according to (a) instead of bis(tert.-butylimido)chromium dichloride. Sulfurylchloride can be additionally used as the chlorine carrier reagent for R2. The sulfurylchloride can be used in an excess to the compound formed from step (a). The ratio of sulfurylchloride to the dioxochromium compound employed can be between 1:1 and 100:1, preferably between 1:1 and 10:1, and especially preferred between 1:1 and 3:1. The reaction is preferably carried out in tetrachloromethane. The reaction temperature here can lie between 0xc2x0 C. and 100xc2x0 C. [32xc2x0 F. and 212xc2x0 F.], preferably between 10xc2x0 C. and 60xc2x0 C. [50xc2x0 F. and 140xc2x0 F.] and especially preferred between 20xc2x0 C. and 60xc2x0 C. [68xc2x0 F. and 140xc2x0 F.].
Special preference is given to catalyst systems in which imidochromium compounds having the general formula I 
are used, wherein the variable have the following meaning:
X independent of each other, stands for fluorine, chlorine, bromine, iodine, NR5R6, NP(R5)3, OR5, OSi(R5)3, SO5R3, OC(O)R5, xcex2-dikatonate, sulfate, dicarboxylates, dialcoholates, BF4xe2x88x92, PF6xe2x88x92, or bulky weakly or non-coordinating anions;
R1 stands for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, whereby the organic radical R1 can also have inert substituents, or SiR33;
R3,R5, R6 independent of each other, stand for C1-C20-alkyl, C2-C20-alkenyl, C6-C20-aryl, alkylaryl having 1 to 10 carbon atoms in the alkyl radical and 6 to 20 carbon atoms in the aryl radical, for hydrogen if the latter is bonded to a carbon atom, whereby the organic radicals R3, R5 and R6 can also have inert substituents;
L is a neutral donor;
n is 0 to 3;
m is 1 for dianionic X, 2 for monoanionic X;
R1 and its preferred embodiments have already been described above. The description of the radicals R3, R5 and R6 is the same as for R5 and R4 elaborated upon above.
The substituents X result from the selection of the appropriate chromium starting compounds that are used for the synthesis of the chromium complexes. Examples of substituents X are, in particular, halogens such as fluorine, chlorine, bromine or iodine, and among these especially chlorine. As additional ligands X, mention should be made of just a few examples, although this is by no means an exhaustive list, namely, BF4xe2x88x92, PF6xe2x88x92, as well as weakly or non-coordinating anions (see, for instance, S. Strauss in Chem. Rev. 1993, 93, pages 927 to 942) and also B(C6F5)4xe2x88x92.
Amides, alcoholates, sulfonates, carboxylates and xcex2-diketonates are especially well-suited. By varying the radicals R5 and R6, it is possible, for example, to fine-tune the physical properties, such as the solubility. Preference is given to C1-C10-alkyl such as methyl, ethyl, n-propyl, n-butyl, tert.-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl as well as vinyl, allyl, benzyl and phenyl as the radicals R5 and R6. The use of some of these substituted ligands X is very much preferred since they can obtained from starting materials that are cheap and readily available. For instance, a particularly preferred embodiment is one where X stands for dimethylamide, methanolate, ethanolate, isopropanolate, phenolate, naphtholate, triflate, p-toluene sulfonate, acetate or acetylacetonate. Dianionic ligands of the type described in greater detail above can also be employed. It is particularly preferred if X stands for chlorine and m equals 2. Designating the ligands X as anions does not specify the type of bond to the transition metal. M. For example, if X is a non-coordinating or weakly coordinating anion, then the interaction between the metal M and the ligand X is more of an electrostatic nature. In contrast, in cases where, for instance, X stands for alkyl, the bond is covalent. The various types of bonds are known to the person skilled in the art.
The donor L has also been described above, thereby n corresponds to the number of neutral donor molecules.
The imidochromium compound I can be monomeric or dimeric, or else polymeric. If it is dimeric or polymeric, than one or more ligands on the chromiumxe2x80x94this can be X, L or else that imido groupxe2x80x94can bridge two chromium centers.
Preferred imidochromium complexes having formula I or III are: methylimidochromium trichloride, ethylimidochromium trichloride, n-propylimidochromium trichloride, iso-propylimidochromium trichloride, n-butylimidochromium trichloride, iso-butylimidochromium trichloride, tert-butylimidochromium trichloride, n-pentylimidochromium trichloride, n-hexylimidochromium trichloride, n-heptylimidochromium trichloride, n-octylimidochromium trichloride, allylimidochromium trichloride, benzylimidochromium trichloride, phenylimidochromium trichloride, naphthylimidochromium trichloride, biphenylimidochromium trichloride, anthranylimidochromium trichloride, 2-chlorophenylimidochromium trichloride, 2-methylphenylimidochromium trichloride, 2,6-dimethylphenylimidochromium trichloride, 2,4-dimethylphenylimidochromium trichloride, 2,6-diisopropylphenylimidochromium trichloride, 2,6-dichlorophenylimidochromium trichloride, 2,4-dichlorophenylimidochromium trichloride, 2,6-dibromophenylimidochromium trichloride, 2,4-dibromophenylimidochromium trichloride, 2,4,6-trimethylphenylimidochromium trichloride, 2,4,6-trichlorophenylimidochromium trichloride, pentafluorophenylimidochromium trichloride, trifluoromethylsulfonlimidochromium trichloride, toluene sulfonylimidochromium trichloride, phenylsulfonylimidochromium trichloride, p-trifluoromethylphenylsulfonylimidochromium trichloride, or 2,6-diisopropylphenylsulfonylimidochromium trichloride, formylimidochromium trichloride, acylimidochromium trichloride, benzoylimidochromium trichloride, naphthoylimidochromium trichloride, anthranoylimidochromium trichloride, 2-cyclobenzoylimidochromium trichloride, 2-chlorobenzyolimidochromium trichloride, 2-methylbenzoylimidochromium trichloride, 2,6-dimethylbenzoylimidochromium trichloride, 2,4-dimethylbenzoylimidochromium trichloride, 2,6-diisopropylbenzoylimidochromium trichloride, 2,6-dichlorobenzoylimidochromium trichloride, 2,4-dichlorobenzolylimidochromium trichloride, 2,6-dibromobenzoylimidochromium trichloride, 2,4-dibromobenzoylimidochromium trichloride, 2,4,6-trimethylbenzoylimidochromium trichloride, 2,4,6-trichlorobenzoylimidochromium trichloride or pentafluorobenzoylimidochromium trichloride.
The catalyst systems according to the invention also contain an activator, component (B), which is put in contact with the chromium complex. Examples of activator compounds are those of the alumoxane type (or aluminoxane), especially methyl alumoxane MAO. Alumoxanes are produced, for example, by means of the controlled addition of water or aqueous substances to alkyl aluminum compounds, especially trimethyl aluminum (for example, U.S. Pat. No. 4,404,344). Alumoxane preparations that are suitable as co-catalysts are commercially available. It is assume that this is a mixture of cyclic and linear compounds. The cyclic alumoxanes can be encompassed by the formula (R7AlO), and the linear aluminoxanes by the formula R7(R7AlO)2AIR72, wherein s indicates the degree of oligomerization and it is a number ranging from about 1 to 50. Advantageous alumoxanes contain essentially alumoxane oligomers having a degree of oligomerization of about 2 to 30 and R7 is preferably an C1-C4-alkyl and especially preferably methyl, ethyl, butyl or isobutyl.
In addition to the alumoxanes, possible activator components are those of the type used in the so-called cationic activation of metallocene complexes. Such activator complexes are known, for example, from EP-B 0,468,537 and from EP-B-0,427,697. In particular, boranes, boroxines or borates such as, for instance, trialkyl borane, triaryl horane trimethyl boroxine, dimethyl anilinium tetraaryl borate, trityletraaryl borate, dimethyl anilinium boratabenzenes or trityl boratabenzenes (see WO-A 97/36937) can be employed as such activator compounds (B). Special preference is given to the use of boranes or borates that have at least two perfluorinated aryl radicals.
Activator compounds having strong oxidizing properties can also be used such as, for instance, silver borates, especially silver tetrakispentafluorophenyl borate or ferrocenium borates, especially ferrocenium tetrakispentafluorophenyl borate or ferrocenium tetraphenyl borate.
Compounds such as aluminum alkyls, especially trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tributyl aluminum, dimethyl aluminum chloride, dimethyl aluminum fluoride, methyl aluminum, dichloride, methyl aluminum sesquichloride, diethyl aluminum chloride or aluminum trifluoride can likewise be employed as activator components. The hydrolysis products of aluminum alkyls with alcohols can also be used (see, for instance, WO-A 95/10546).
Furthermore, alkyl compounds of lithium, magnesium or zinc such as, for example, methyl magnesium chloride, methyl magnesium bromide, ethyl magnesium chloride, ethyl magnesium bromide, butyl magnesium chloride, phenyl magnesium chloride, dimethyl magnesium, diethyl magnesium, dibutyl magnesium, methyl lithium ethyl lithium, methyl zinc chloride, dimethyl zinc or diethyl zinc can be used as activator compounds.
Especially preferred catalyst systems are those in which the activator compound (B) is selected from the following group: aluminoxane, trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride, methyl aluminum dichloride, ethyl aluminum chloride, methyl aluminum sesquichloride, dimethylanilinium tetrakispentafluorophenyl borate, trityltetrakispentafluorophenyl borate or trispentafluorophenyl borane.
Sometimes, it is desirable to make use of a combination of several activators. This is a known procedure, for example, with metallocenes in which boranes, boroxines (WO-A 93/16116) and borates are often used in combination with an aluminum alkyl. Generally speaking, a combination of various activator components with the chromium complexes according to the invention is likewise possible.
The amount of activator compounds to be used depends on the type of activator. Generally speaking, the molar ratio of chromium complex (A) to activator compound (B) can range from 1:0.1 to 1:10,000, preferably from 1:1 to 1:2000. The molar ratio of chromium complex (A) to dimethylanilinium tetrakispentafluorophenyl borate, trityltetrakispentafluorophenyl borate or trispentafluorophenyl borane preferably lies between 1:1 and 1:20, and especially preferred between 1:1 and 1:10, with respect to methyl aluminoxane, preferably between 1:1 and 1:2000 and especially preferred between 1:10 and 1:1000. Since many of the activators such as, for instance, aluminum alkyls are concurrently employed to remove catalyst poison (so-called scavengers), the quantity employed also depends on the purity of the other substances used. The person skilled in the art, however, can determine the optimal amount by means of simple experimentation.
The mixture with the activator compound can be carried out in a wide array of aprotic solvents, preference being given to alkanes such as pentane, hexane, heptane and octane, or to aromatic compounds such as benzene, toluene and xylene, whereby pentane, hexane, heptane and toluene are particularly preferred. Solvent mixtures, especially of alkanes with aromatic compounds, are also advantageous for purposes of adjusting to the solubilities of the catalyst system.
The mixing with the activator compound takes place at temperature between xe2x88x9250xc2x0 C. and 150xc2x0 C. [xe2x88x9258xc2x0 F. and 302xc2x0 F.], preferably between 10xc2x0 C. and 50xc2x0 C. [50xc2x0 F. and 122xc2x0 F.], especially preferred between 15xc2x0 C. and 30xc2x0 C. [59xc2x0 F. and 86xc2x0 F.].
For the polymerization, one or more of the catalyst systems according to the invention can be used simultaneously. As a result, for example, bimodal products can be obtained. A wider product spectrum can also be achieved by using the imidochromium compounds in combination with another polymerization-active catalyst (C). In this context, at least one of the catalyst systems according to the invention is used in the presence of at least one catalyst (c) commonly employed for the polymerization of olefins. Here, preference is given to the use of Ziegler-Natta catalyst on the basis of titanium, classic Phillips catalysts on the basis of chromium oxides, metallocenes, the so-called constrained geometry complexes (see, for instance, EP-A 0,416,815 or EP-A 0,420,436), nickel and palladium bis-imine systems (for their preparation, see WO-A 98/03559), iron and cobalt pyridine-bis-imine compounds (for this preparation, see WO-A 98/27124) or chromium pyrrol compounds (see, for example EP-A 0,608,447) as the catalysts (C). Thus, by means of such combinations, for example, bimodal products can be produced or comonomers can be generated in situ. In this context, depending on the selection of the catalyst, it is advantageous to employ one or more activators. The polymerization catalysts (C) can likewise be on a support and they can be contacted simultaneously or in any desired order with the catalyst system according to the invention or with its components. A pre-activation of the catalyst (C) with an activator compound (B) is likewise possible.
The description and the preferred embodiments of R1 to R6 and for X in the imidochromium compounds II and III as well as in the processes for the production of the chromium complexes I, III, IV and VI, the former employing the imidochromium compound V, are all the same as elaborated upon above. The reaction conditions have largely been described above as well.
Z and its preferred embodiments stand for the same described above for X and additionally also for alkyls or aryls, especially preferred for methylene trimethylsilyl, benzyl or mesityl.
The processes for the production of the chromium complexes III and V are fundamentally carried out under the same conditions, as a result of which the reaction parameters will be described together below.
An essential reaction step is the contacting of the N-sulfinyl compound with the corresponding dioxochromium compound. The dioxochromium compounds have likewise been described above. Here as well, the preferred dioxochromium compound is dioxochromium dichloride. The N-sulfinyl compounds have likewise been described above. The preferred embodiments result from the preferred embodiments of the radicals R1 or R2 of the imido group of the chromium complex being formed (see above). The reaction step has already been described above for the reaction step (a). This can be followed by a regular purification step, for instance, recrystallization or filtration.
The process according to the invention for the polymerization of olefins can be combined with all of the technically known polymerization methods at temperatures within the range from 0xc2x0 C. to 300xc2x0 C. [32xc2x0 F. to 572xc2x0 F.] and at pressures ranging from 1 bar to 4000 bar. Therefore, the advantageous pressure and temperature ranges at which to carry out the process depend to a great extent on the polymerization method. Thus, the catalyst systems used according to the invention can be employed in all of the known polymerization processes such as, for example, a high-pressure polymerization process in tubular-flow reactors or autoclaves, in suspension-polymerization processes, in solution-polymerization processes or in gas-phase polymerization. In the case of the high-pressure polymerization process, which is normally carried out at pressures between 1000 and 4000 bar, especially between 2000 and 3500 bar, high polymerization temperatures are usually set as well. Advantageous temperature ranges for these high-pressure polymerization processes lie between 200xc2x0 C. and 300xc2x0 C. [392xc2x0 F. and 572xc2x0 F.]. especially between 220xc2x0 C. and 270xc2x0 C. [428xc2x0 F. and 518xc2x0 F.]. When it comes to the lower-pressure polymerization process, the selected temperature is usually at least a few degrees below the softening point of the polymer. The polymerization temperature can be between 0xc2x0 C. and 180xc2x0 C. [32xc2x0 F. and 356xc2x0 F.]. In particular, temperature between 50xc2x0 C. and 180xc2x0 C. [122xc2x0 F. and 356xc2x0 F.], preferably between 70xc2x0 C. and 120xc2x0 C. [158xc2x0 F. and 248xc2x0 F.] are set in these polymerization processes. Among the polymerization methods mentioned, preference is given according to the invention to gas-phase polymerization, especially in gas-phase fluidized-bed reactors, as well as to suspension polymerization, particularly in loop-type reactors and stirred-tank reactors as well as to solution polymerization. Gas-phase polymerization can also be performed in the so-called condensed, supercondensed or supercritical mode of operation. Different or else the same polymerization methods can optionally also be connected with each other in series so as to create a polymerization cascade. Moreover, in order to regulate the polymer properties, an additive such as, for instance, hydrogen, can also be used in the polymerization processes.
Using the process according to the invention, various olefinically unsaturated compounds can be polymerized, which also includes copolymerization. In contrast to a few known iron and cobalt complexes, the transition-metal complexes used according to the invention exhibit good polymerization activity, even with higher xcex1-olefins, so that special mention needs to be made of their suitability for copolymerization. Aside from ethylene and xcex1-olefins having 3 to 12 carbon atoms, examples of olefins are also internal olefins and non-conjugated and conjugated dienes such as butadiene, 1,5-hexadiene or 1,6-heptadiene, cyclic olefins such as cyclobutene, cyclopentane or norbornene and polar monomers such as acrylic acid ester, acrolein, acrylonitrile, vinylether, allylether and vinylacetate. Vinyl-aromatic compounds such as styrene can also be polymerized by means of the process according to the invention. Preferably, at least one olefin selected from the group consisting of ethene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, cyclopentene and norbornene is polymerized. A preferred embodiment of the process according to the invention is characterized in that mixtures of ethylene with C3-C8-xcex1-olefins are used as the monomers.
In this context, the chromium complex can be brought into contact with the activator compound or compounds either before or after contacting with the olefins to be polymerized. Another possibility is pre-activation with one or more activator compounds prior to mixing with the olefin and the further addition of the same or different activator compounds after this mixture has been contacted with the olefin. As a rule, pre-activation is conducted at temperatures between 10xc2x0 C. and 100xc2x0 C. [50xc2x0 F. and 212xc2x0 F.], preferably between 20xc2x0 C. and 80xc2x0 C. [68xc2x0 F. and 176xc2x0 F.].
Furthermore, more than one of the catalyst systems according to the invention can be simultaneously brought into contact with the olefin to be polymerized. This has the advantage that a wide range of polymers can be thus created. In this manner, bimodal products, for example, can be produced.
The catalyst systems according to the invention can optionally also be immobilized on an organic or inorganic support and then be used in the polymerization in this supported form. This is a common method employed to avoid reactor deposits and to regulate the polymer morphology. Preferably support materials are silica gel, magnesium chloride, aluminum oxide, mesoporous materials, alumosilicates and organic polymers such as polyethylene, polypropylene or polystyrene and especially silica gel or magnesium chloride.
One or more of the catalyst systems according to the invention can be immobilized on a support. The components of the catalyst system can be put into contact with the support in varying orders or all at the same time. This is usually done in an inert solvent that can be filtered off or evaporated after the immobilization procedure. The use of the still moist, supported catalyst is also possible. For instance, the support can be first mixed with the activator compound or compounds or else the support can first be contacted with the polymerization catalyst. Pre-activation of the catalyst with one or more activator compounds prior to the mixing with the support is also possible. The amount of chromium complex (A) in mmoles per gram of support material can vary widely, for example, from 0.001 to 1 mmole/g. The preferred quantity of chromium complex (A) per gram of support material lies between 0.001 and 0.5 mmole/g, especially preferably between 0.005 and 0.1 mmole/g. In one possible embodiment, the chromium complex (A) can also be produced in the presence of the support material. Another type of immobilization is the pre-polymerization of the catalyst system with or without a prior supporting step.
Polymers of olefins can be produced by means of the process according to the invention. The term polymerization as employed here to describe the invention comprises both polymerization and oligomerization, that is to say, oligomers and polymers having molecular weights within the range from about 56 to 4,000,000 can be produced by means of this process.
In view of their good mechanical properties, the polymers produced with the catalyst system according to the invention are particularly suitable for the manufacture of films, fibers and molded articles.
The catalysts according to the invention display moderate levels of productivity.
The comparative examples for the bis-imidochromium compounds described in EP-A 0,641,804 show that the monoimide compound according to the invention, (C6F5N)CrCl5, yielded higher levels of activity. In comparison to the bis-imido compounds, the norbornene polymerization did not yield any metathesis products.
The new process for the production of bis-imidochromium compounds is a one-pot synthesis. In this manner, up to two synthesis steps can be dispensed with in the preparation of bis(arylimido)chromium complexes.
N-sulfinylamines have been employed by S. Chenini and M. Pizzotti (Inorg. Chim. Acta [Inorganic chemical archives] 42, (1980), 65) for the synthesis of molybdenum imido compounds. It was assumed that the released SO2 would reduce the chromium species when the reduction-prone chromium(VI)dioxo-compounds are used. Surprisingly, however, this was not observed.
The examples that follow serve to illustrate the invention.
Unless otherwise indicated, all of the work was performed in the absence of air and moisture. Toluene was dried and distilled off over a molecular sieve column or potassium-benzophenone. Triethyl aluminum (2 M in heptane) and MAO (methyl aluminoxane 30% in toluene) were obtained from the Witco GmbH and Albermarle companies.
Analytical Methods
The elementary analyses were carried out using a Herseus CHN-Rapid unit.
The IR spectra were obtained with a Nicolet 510M as a Nujol trituration between KBr plates.
The xcex7 value was determined with an automatic Ubbelohde viscosimeter (Laudar PVS 1) with Decalin as the solvent at 130xc2x0 C. [266xc2x0 F.] (ISO 1628 at 130xc2x0 C. [266xc2x0 F.], 0.001 g/mL of Decalin).
El mass spectra were obtained with a Varian MAT CH7 unit.
The melting points were determined by means of a Melting Point B-540 device manufactured by the Buechi company.
The NMR spectra were obtained with a Bruker ARX 200 unit or with a Bruker AMX 300 unit.
Key to the abbreviations used in the following tables:
Cat. ex. Catalyst according to the example
yield yield of polymer
gP grams of polymer
Tg glass transition temperature
Tm melting temperature
h Staudinger index (viscosity)
tBu tert.-butyl
Ts para-toluene sulfone
Bz benzoyl
Tf trifluoromethane sulfone